The NLM PubMed Project

The NLM PubMed Project

Introduction

PubMed is a project developed by the National Center for Biotechnology Information (NCBI) at the National Library of Medicine (NLM), located at the National Institutes of Health (NIH). It has been developed in conjunction with publishers of biomedical literature as a search tool for accessing literature citations and linking to full-text journals at Web sites of participating publishers.

Publishers participating in the PubMed project supply NLM with formatted citations prior to or at the time of publication, and NLM adds them to the PubMed search system. If the publisher has a WWW site that offers full text of its journals, PubMed provides links to that site. In addition, PubMed provides a WWW Citation Matcher service, which allows publishers (or other outside users) to match up their own citations to PubMed entries, using bibliographic information such as journal, volume, issue, page number, and year. This permits publishers easily to link from references in their published articles directly to entries in PubMed.

Database Coverage

The PubMed search system provides access to the PubMed database of bibliographic information, which is drawn primarily from MEDLINE and PREMEDLINE. In addition, for participating journals that are indexed selectively for MEDLINE, PubMed includes all articles from that journal, not just those that are included in MEDLINE. Finally, PubMed also provides access to the molecular biology databases included in NCBI's Entrez retrieval system. It is expected that access to additional National Library of Medicine databases will be added in the future.

MEDLINE (MEDlars onLINE) is the National Library of Medicine's (NLM) premier bibliographic database covering the fields of medicine, nursing, dentistry, veterinary medicine, the health care system, and the preclinical sciences. The MEDLINE file contains bibliographic citations and author abstracts from approximately 3,900 current biomedical journals published in the United States and 70 foreign countries. The file contains approximately 9 million records dating back to 1966. Coverage is worldwide, but most records are from English-language sources or have English abstracts. Each MEDLINE record is identified with a unique identifying number called a MEDLINE UID (MUID in PubMed). Citations for MEDLINE are created by the National Library of Medicine, International MEDLARS partners, and cooperating professional organizations. MEDLINE records are incorporated into PubMed weekly, and are also assigned a PubMed unique identifier (PMID).

Introduced by the National Library of Medicine in August 1996, the PREMEDLINE database provides basic citation information and abstracts before the full records are prepared and added to MEDLINE. New records are added to PREMEDLINE daily, and each record receives a MEDLINE UI from the beginning. After MeSH terms, publication types, GenBank accession numbers, and other indexing data added, the completed records are added weekly to MEDLINE, and deleted from the interim PREMEDLINE database. PREMEDLINE records are incorporated into PubMed on a daily basis, and assigned a PubMed unique identifer (PMID).

Some of the PubMed bibliographic data is transmitted to PubMed directly by publishers, and assigned a PubMed identifier (PMID). This data is also used by the National Library of Medicine as input for PREMEDLINE. For a short period of time, while being processed for PREMEDLINE, this data may appear only in PubMed. When a publisher-supplied citation is subsequently incorporated into PREMEDLINE, it is updated to include the UI in addition to the PMID. Later, when the record receives its MeSH terms and other MEDLINE database elements, it will be updated again. Publishers may also, at any time, submit corrections and updates of their citations to PubMed.

Some of the articles received electronically from publishers, however, will never be replaced by PREMEDLINE or MEDLINE articles. This occurs when a particular article in a selectively indexed journal is out of scope for MEDLINE (such as a geology article in a general scientific journal like Science or Nature), but the publisher provides PubMed with electronic information for the entire journal. These records have only a PMID, and no UI.

PubMed Journal Information

The PubMed Journal Browser allows you to look up journal names, MEDLINE abbreviations, or ISSN numbers for journals that are included in the PubMed system.

See MEDLINE Journals With Links to Publisher Web Sites for a list of Web-based journals to which PubMed currently provides links. New journals are regularly added. Web-based journals usually contain the full-text of the original article, but this is not always the case. It varies by publisher and journal. Some sites may require that you register, subscribe, or pay a fee in order to view the full text of an article. Contact the journal publishers as noted on their individual Web sites for specific access information.

A full list of the PubMed journals is also available by ftp.

Linking to PubMed

Users can create WWW links to retrieve and display one or more PubMed records, using HTML syntax. See Linking to PubMed and Entrez Databases for detailed information on how to link to specific citations, how to create links that perform searches, how to use Boolean expressions, and how to specify output formats.

PubMed Citation Matcher

The Citation Matcher allows users to match their own list of citations to PubMed entries, using bibliographic information such as journal, volume, issue, page number, and year. The Citation Matcher reports the corresponding PMID or UI. This number can then be used to easily to link to PubMed. This service is used heavily by publishers or other database providers who wish to link from bibliographic references on their WWW sites directly to entries in PubMed.

This facility allows you to find the PubMed ID or the MEDLINE UI of any article in the PubMed database, given its bibliographic information (journal, volume, page, etc.).

Who To Contact

If you have any questions, please send e-mail to us at pubmed@ncbi.nlm.nih.gov


Last Modification: Jan 9, 1998